The form-fill-seal (FFS) systems have become an efficient and convenient way of packaging many products, particularly, products which are fluid. Since the basic container is a pouch formed of thermoplastic film, the weight and expense of metal cans is eliminated. The machines and methods basically are either horizontal form-fill-seal (HFFS) systems or vertical form-fill-seal (VFFS) systems.
Machines and processes for the forming, filling, and sealing of packages made from a continuous web or film of material are well known in the art. These machines comprise a supply of packaging film, a former and edge sealer for the forming of the film into a continuous hollow tube with a overlap edge seal, and reciprocating sealing and cutting jaws for sealing and cutting the tube into a consecutive series of sealed packages. The popularity of such machine is important due to their simplicity and speed of operations. A wide variety of articles can be packaged ranging from potato chips to tomato paste. A typical prior art VFFS machine for packaging articles such as potato chips is disclosed in U.S. Pat. No. 4,563,862 which issued on Jan. 14, 1986 to H. T. McElvy.
As mentioned above, the basic idea in a VFFS machine is to form a continuous tube by folding a continuous sheet of film around a vertically mounted former or mandrel, sealing the overlapped seam against the mandrel to form a tube, and then transversely flattening and sealing the tube at intervals as it is filled from above through the mandrel or former. Readily flowable materials such as tomato paste, liquid detergents, syrups, and liquids in general will flow reliably, and fill the package or container. However, when a solid/liquid mixture is delivered to a funnel or receiving chute above the tubular forming mandrel there will be a tendency for sticky materials such as the pasta phase of a soup to stick to the chute or to the delivery receptacle. Accordingly, it is a general object of the present invention to provide a delivery or filling system for a solid/liquid mixture wherein the solids are sticky and maintain the critical liquid/product ratio.
In one prior art system, a bucket conveyor is employed to deliver the entire charge for a container to a delivery chute and while the bucket is tilted and upturned over the delivery chute, it is re-tilted and banged against the limit stop in order to shake loose any additional solid product. However, the very sticky pasta pieces such as noodles do not, with any degree of reliability, dislodge by the banging and shaking. In addition, such banging and shaking places undue wear and stress on the equipment and is to be avoided. Accordingly, it is another object of the present invention to achieve a reliable and satisfactory method of removing sticky solids from a delivery vessel without resorting to banging or shaking of the delivery vessel.
In U.S. Pat. No. 4,606,174 which issued on Aug. 19, 1986, a VFFS process is disclosed for making packages containing a liquid product with a certain proportion of solid particles such as soup with pieces of fruit. In order to maintain the desired proportions of liquid and solid in a fast working machine, the solid and liquid parts are fed separately by means of two filling pipes and the feeding of the liquid contents ends only after the feeding of the solid particles has ended. However, in this method, the solid particle mix has to be pumped through a double walled pipe which extends down into the forming mandrel thus presenting a complicated arrangement and the associated problems of pumping a liquid with a high proportion of solids. Accordingly, it is another object of the present invention to present a method of filling which avoids the necessity of pumping a mixture containing a high proportion of solids.
Other form-fill-seal devices of interest include U.S. Pat. No. 4,407,108 which issued to S. R. Craig on Oct. 4, 1983; U.S. Pat, No. 4,617,785 which issued on Oct. 21, 1986 to H. Chikatani et al; and U.S. Pat. No. 4,768,411 which issued on Sep. 6, 1988 to Philip Su.
The objects mentioned in the foregoing paragraphs are achieved by the invention which is described below.